The Active Absorption of Certain Metabolites by Helminths

Abstract

The relationship between the parasite and its host is essentially an ecological problem. Unlike most ecological problems, however, where the forms, which contribute in such an ill-defined manner to the environment of each other, may be separated by an appreciable and variable space, the problem of the hostparasite relationship is usually one of an intimate association in which the effects of each on the other are more nearly direct and, perhaps, far more complicated. It is, therefore, inconceivable that any rational thought could be given to the physiology, biochemistry, or any other aspect of a parasite's existence without adequate consideration of its host and their interrelationship. This has been adequately demonstrated by many experiments involving such host variables as nutrition, hormone balance, and host type, where even the physical characteristics of the parasite may be altered (Kuntz and Chandler, 1956), as well as the physiological (Daugherty, 1955).